Nowadays, touch control techniques have become a mainstream in multimedia and communication industries. For security and power-saving purposes and to avoid unintentional triggering, touch control can be locked when a touch-sensitive display has been suspended from use for preset duration. Afterwards, the touch control can be recovered by an unlocking operation on the touch-sensitive display.
Current solutions for unlocking touch control of a touch screen terminal, e.g. a smart phone, are commonly implemented with a sliding gesture. FIG. 1A schematically illustrates unlocking means used in an Apple® iPhone 110, wherein the touch control can be unlocked by dragging an unlock image 111 along a channel 112 to the end of the channel 112, e.g. from left to right. FIG. 1B and FIG. 1C schematically illustrate examples of unlocking means used in mobile phones 120 and 130 for Android™. In the example shown in FIG. 1B, the touch control can be unlocked by dragging an unlock image 121 downwards to a specific position 122. In the example of FIG. 1C, the touch control can be unlocked by dragging a selected one of functional icons M, P and H to a specific position 132. While unlocking the touch control, a desired function corresponding to the function icon is also activated.
The above-mentioned unlocking means, even though implemented with different details, have a common algorithm for unlocking the touch control. That is, it is essential to drag an unlock image from a locking position A to an unlocking position X through a defined path P, as schematically illustrated in FIG. 1D. Due to confinement of the unlocking position X and the unlocking path P, the unlocking means is not user-friendly enough.